Apparatus for automatically distributing a determined amount of liquid

ABSTRACT

An apparatus for automatically distributing a determined amount of liquid in which a plate is pressed against a part of a tube made of flexible and resilient material along a certain length thereof to eject air in the pressed part of the tube. The plate is moved away from the tube with a pipette provided at the tube end being kept inserted into liquid in a liquid supply container to admit into the pipette the same amount of liquid as the ejected air. Then, under this condition, the pipette is inserted into a test tube and the plate is again pressed against the part of the tube to dispense the liquid in the pipette into the test tube.

' United States Patent Mochida Oct. 21, 1975 1 APPARATUS FOR AUTOMATICALLY [56] References Cited DISTRIBUTING A DETERMINED AMOUNT UNITED STATES ATEN 0F LIQUID 3,437,050 4/1969 Hrdina 417/476 [76] Inventor: Ei Mochida, 5-4, 2-chome,

Komagome Toshima-ku, Tokyo, Primary ExaminerHouston S. Bell, Jr. Japan Attorney, Agent, or Firm-C0nnolly and Hutz [22] Filed: Apr. 10, 1974 211 App]. No.2 459,688 [57] ABSTRACT An apparatus for automatically distributing a determined amount of liquid in which a plate is pressed [30] Forelgn Apphcatlon Pnomy Data against a part of a tube made of flexible and resilient Apr. 10, 1973 Japan 48-48040543 material al ng a ertain length thereof t eject air in the pressed part of the tube. The plate is moved away from the tube with a pipette provided at the tube end 417/474 being kept inserted into liquid in a liquid supply con- [51] Int. CLZ 367C 3/00 tainer to admit into the pipette the ame amount of Field of Search 141/18, 130, 2, 25, 26, liquid as the ejected air. Then, under this condition,

Tl MOI To ii I FL B0} :ss4 B2 3 Ra o ii-3 $3 J the pipette is inserted into a test tube and the plate is again pressed against the part of the tube to dispense the liquid in the pipette into the test tube.

4 Claims, 2 Drawing Figures US. Patent Oct. 21, 1975 Sheet 2 0f 2 APPARATUS FOR AUTOMATICALLY DISTRIBUTING A DETERMINED AMOUNT OF LIQUID BACKGROUND OF THE INVENTION This invention relates to an apparatus for automatically distributing a determined amount of liquid into every one of a plurality of containers, and more particularly, to an apparatus in which a tube of flexible and resilient material is pressed along a predetermined length thereof and then released to admit liquid into the tube to distribute a determined amount of liquid into every one of a plurality of test tubes or the like.

There often arises a necessity of distributing, for instance, a determined amount of liquid medicine in a flask into every one of a plurality of test tubes or the like. However, it is usually very troublesome and timeconsuming to supply such liquid medicine intermittently, and none of the known systems has been satisfactory in the accuracy of the amount supplied, the distributing speed and the responsiveness of the apparatus.

SUMMARY OF THE INVENTION The present invention is a proposal to overcome the abovementioned problems of the prior art, and a primary object is to provide an apparatus for automatically distributing a determined amount of liquid in which a part of a tube made of a flexible and resilient material is pressed and then released so as to admit a determined amount of liquid into the tube. Thereafter the tube is pressed again to discharge the liquid.

Another object of the present invention is to provide an apparatus of the type described in which a pipette is securely attached to the end of the tube and the pipette is moved between a flask and one of the test tubes to suck up liquid from the flask into the pipette and discharge it into test tubes to thereby effect intermittently transfer of liquid between the flask and the test tubes.

Still another object of the present invention is to provide an apparatus of the described type in which a push plate for pressing the tube along a predetermined length thereof is operated by a suitable drive was to admit liquid into or eject it from the tube through a pipette provided at the end of the tube.

Still another object of the present invention is to provide an apparatus in which the liquid delivered is controlled by adjusting the inner diameter of the tube through the increase or decrease of the tube tension.

BRIEF DESCRIPTION OF THE DRAWINGS Novel features and advantages of the present invention in addition to those mentioned above will become apparent to those skilled in the art from a reading of the following detailed description in conjunction with the accompanying drawings wherein similar reference characters refer to similar parts and in which:

FIG. 1 is a longitudinally sectional side elevation of an apparatus for automatically distributing a determined amount of liquid, according to the present invention; and

FIG. 2 is a plan view of the test tube mechanism of the apparatus of FIG. 1, with some parts shown in section.

DETAILED DESCRIPTION OF THE INVENTION Referring in more particularity to the drawing, a fixed transparent flat plate I of plastic is partly punched to form circular holes Ho, and H0 A flexible plastic tube T, comprising the primary portion of a pump, is fixed to the flat plastic plate I in contact therewith-by fittings J,,, J, and J The tube T has fins H, and H, so that tension may be imparted to the tube T as the end portion K, of a lever K moves against the fin H,. The fitting J abuts the fin H to thereby prevent that end of the tube from moving with the other end of the tube when the lever K is manipulated. The lever K is arranged to swing about a fixed pivot L in accordance with forward or backward movement of a screw type manipulator N threaded through a threaded hole formed in a fixed plate 0. The purpose of the lever K is to stretch or contract the flexible tube T to reduce or enlarge the inner diameter thereof to thereby adjust the amount of liquid drawn into or discharged out of the tube.

The tube T extends upward through the hole H0, in the plastic plate I and then curves in the form of S above the plastic plate, as shown in the drawing. Tube T connects with a fine metal tube T,. The fine metal tube T, passes through the fixed metal fittings Me,, Me, where it is horizontally supported.The end portion of the tube T, on the downstream side thereof is bent downwardly at a right angle, and a plastic pipette P is exchangeably inserted into the lowermost end of the downwardly bent portion of the tube T,.

The upper end portion of an upstream blocking means P, terminates at a relatively obtuse-angled edge adapted to intersect at right angles with the horizontal portion of the tube T. The blocking means P, is pulled downward, through a pin G," provided inside thereof, an arm B, and a pin G,", and a spring Sp, fixed at its lower end by a fixing member Q, to normally hold the blocking means P, at an inoperative position relative to the tube T.

A lever B, pivoted by a fixed pin 6,. is connected at one end to the am B, by the pin G," at the other end to a shaft S, through a pin G, and a wire W.

The shaft S, extends downward through a fixed meta support M,, with the intermediate portion of the shaft;

passing through and being fixed to an iron core F, in a solenoid coil C,. The solenoid coil C, is fixed and arranged in such a manner that when energized it pulls the core F, downwardly. As the core F, moves in a downward direction, the shaft S, is also pulled downwardly thereby pulling the pin 0,. Downward movement of the pin G, pushes the upstream blocking means P, to its operative position so as to squeeze the tube T.

In order to avoid rapid movement of the core F, upon activation of the solenoid coil C,, an oil damper ,D, is

associated with the shaft 5,, the oil damper being filled with buffer oil to offer resistance to movement of pis-. ton d, secured to the shaft 8,. Packings R, are provided for preventing oil leakage.

A push plate P, has a flat top face of predetermined as that for operating the blocking means P,, while the former has two solenoids, both of which are energized or de-energized simultaneously to move the push plate P up or down, respectively. An auxiliary push plate P provided downstream from the push plate P is substantially the same as the plate P in both structure and operation, except that the former is moved by one solenoid rather than two.

The metal tube T, has a fin connected to a T-shaped lever B by a pin G inserted through an elongated hole formed in the fin. The lever B is swingable' about a fixed pin G to move the metal tube T horizontally by a spring-solenoid combination similar to that used in connection with the upstream blocking means P That is, as apparent from the drawing, the pipette P stays above the test tube I, when the solenoid coil is deenergized, but when the coil is energized, the pipette P is moved to a location immediately above a liquid supply container FL supported on a stand U fixedly mounted atop a shaft S which extends through a fixed metal support M The shaft 8;; is directly connected to an iron core F of a solenoid coil C The shaft further extends from the core F into an oil damper P A spring SP is fixed at its lower end to a fixing member 0;; and is joined at a point V to the stand U to always pull it downwardly. In the thus arranged mechanism, the stand U is forced upwards when the coil C is energized.

A disc-shaped turntable Ta is shown in section in the drawing. This turntable Ta is so designed that a plurality of test tubes may be placed erect along the circumference of the table. The turntable Ta is connected to a ratchet Ra through a shaft S so that the turntable is rotatable around the shaft S supported on a fixed base plate Ba. The turntable moves intermittently by amount equal to the distance from one test tube receiving station to the next with one motion of the ratchet Ra.

The solenoid coil C functions to move the piston S vertically to push up one of the test tubes t It is essential for this purpose that, when the solenoid coil is deenergized, the top end of the piston S. extends through a hole provided in the base plate Ba and stays flush with the upper surface of the plate Ba. Arrangement is also made in such a manner that the piston S when operated,'pushes the test tube upwardly to the optimum position for the test tube to receive liquid from the pipette.

FIG. 2 is a plan view of the right half portion of the turntable Ta for feeding the test tubes together with the left half portion of the driving structure therefor.

The liquid supply container FL is supported on the stand U as described above in conjunction with FIG. 1. The ratchet Ra has teeth equal in number to the holes formed in the turntable for holding the test tubes erect therein and is adapted to turn the turntable Ta via the shaft 8,, intermittently through the distance from one hole to another at each movement. A pawl X engages the ratchet Ra and the pawl is located at one end of a spring Y secured at its other end to a block Z so that the ratchet is held securely at a determined position after every motion thereof. A lever X having a pawl S for driving the ratchet Ra is pivotally mounted by a pin G on a bar 8,, normally pulled by a spring SP fixed at its end opposite to the bar side. The bar 3;, is retained in the position shown in the drawing in contact with an end of a screw St threaded through a fixed block Z Thus, when the solenoid coil C is energized, the iron core F is attracted into the coil to pull the bar 8;, toward the coil through a bar B a pin G a bar 8;,

and a pin G The bar 8;, swings about the shaft S until it engages the end of a screw St threaded through a block Z At this position, the pawl S at the end of the lever X is allowed to advance over one tooth of the ratchet Ra and is then fitted between the one tooth and the next tooth by the action of a spring SP When the coil C is de-energized, the bar 8;, is returned to its original position by the action of spring SP and, accordingly, the lever X pushes the engaged tooth of the ratchet Ra which allows it to turn with the turntable in the direction of the arrow of FIG. 2 through a distance sufficient to bring the next piece of test tube to the position below the pipette P.

In the operation of the thus arranged apparatus, first a plurality of test tubes 1,, t t etc., are set erect on the turntable as shown in FIG. 2. Then sample liquid is put into the flask FL and the pipetting operation is performed automatically to pour a predetermined amount of the liquid in the flask FL into every one of the test tubes. The pipetting operation is described in detail below.

For effecting the operation, electric current is supplied to or cut-off from the respective solenoid coils in given sequence, and such electric current may be controlled by a cam and limit switch mechanism. The upstream blocking means P, is kept in its operative position to block the tube T throughout the operation of the apparatus. To this end, an electric current is kept applied to the solenoid coil C through a separate switch throughout the operation.

Then, electric current is supplied to the respective coils associated with the push plate P and tube T,

v which together constitute the liquid dispensing mechanism. The plate P is raised up while the pipette P is moved to a location right above the flask FL. Then the flask FL is raised up so that the end of the pipette P is submerged in the liquid in the flask. Thereafter, the push plateP is moved downwardly to its inoperative position to thereby suck a determined amount of liquid into the pipette P. The flask FL is then moved down to its original position and the pipette P is moved back to its position above the test tube t Then the shaft 8., is raised up to push up the test tube 2 so that the end of the pipette P is inserted into the test tube Thereafter, the push plate P is again actuated to press the tube T to discharge the liquid in the pipette P into the test tube t Then the auxiliary push plate P is also brought into its operative position to squeeze the tube T to ensure perfect discharge of liquid in the pipette P. The shaft 8;, is then lowered to bring the test tube down to its original position.

Upon completion of the above-mentioned operation, an electric current is applied to the coil C and then cut-off so as to effect one motion of the ratchet Ra for bringing the next test tube t to the position of t, on the turntable. This is followed by movement of the push plate P and auxiliary push plate P to their respective inoperative positions, thus completing one cycle of operation.

- With repetition of such cycle of operation, the liquid in the flask FL is distributed accurately in a predetermined amount into every one of the test tubes. For energizing or deenergizing all of the coils in the abovementioned sequence and at suitable time intervals for accomplishing the above-mentioned operation, it is possible to use a usual interrupter composed of a cam and switch combination, as is well known.

What is claimed is:

1. An apparatus for automatically distributing a predetermined amount of liquid from a liquid supply container into each one of a plurality of containers comprising in combination: a tube made of flexible and resilient material and disposed along a flat plate, an endopened pipette connected to the doyvnstream end of the tube, upstream blocking means closing the tube, a primary push plate between the pipette and the upstream blocking means arranged to reciprocate between an operative position where the push plate presses a section of the tube against the flat plate and an inoperative position where the push plate is away from the tube which allows the tube to return to its original shape, an auxiliary push plate adjacent the primary push plate constructed and arranged to squeeze the tube after the primary push plate moves to its operative position to ensure discharge of the liquid in the pipette, and driving means for moving the pipette between the liquid supply container and the plurality of containers into which the liquid in the supply container is to be distributed.

2. An apparatus as in claim 1 wherein the connection of the pipette to the flexible and resilient tube includes a stiff tube slidably disposed between the pipette and the flexible tube, the flexible tube being disposed horizontally along the flat plate and the lower end of the pipette being open, and wherein the driving means is also connected to move the metal tube in a longitudinal direction whereby the liquid supply container and one of the plurality of containers into which the liquid in the supply container is to be distributed are alternatively moved up and down at predetermined intervals in the vertical direction immediately below the pipette.

3. An apparatus as in claim 1 wherein the flexible and resilient tube is fixedly secured to the flat plate at a por' tion of the tube, and means for adjusting the length of the tube by stretching that tube portion.

4. An apparatus as in claim 2 wherein the plurality of containers into which the liquid isto be distributed are arranged annularly along the circumference of a turntable so as to be disposed immediately below the pipette one after another, and support means for the container disposed immediately belowsaid pipette for elevating the container at that location. 

1. An apparatus for automatically distributing a preDetermined amount of liquid from a liquid supply container into each one of a plurality of containers comprising in combination: a tube made of flexible and resilient material and disposed along a flat plate, an end-opened pipette connected to the downstream end of the tube, upstream blocking means closing the tube, a primary push plate between the pipette and the upstream blocking means arranged to reciprocate between an operative position where the push plate presses a section of the tube against the flat plate and an inoperative position where the push plate is away from the tube which allows the tube to return to its original shape, an auxiliary push plate adjacent the primary push plate constructed and arranged to squeeze the tube after the primary push plate moves to its operative position to ensure discharge of the liquid in the pipette, and driving means for moving the pipette between the liquid supply container and the plurality of containers into which the liquid in the supply container is to be distributed.
 2. An apparatus as in claim 1 wherein the connection of the pipette to the flexible and resilient tube includes a stiff tube slidably disposed between the pipette and the flexible tube, the flexible tube being disposed horizontally along the flat plate and the lower end of the pipette being open, and wherein the driving means is also connected to move the metal tube in a longitudinal direction whereby the liquid supply container and one of the plurality of containers into which the liquid in the supply container is to be distributed are alternatively moved up and down at predetermined intervals in the vertical direction immediately below the pipette.
 3. An apparatus as in claim 1 wherein the flexible and resilient tube is fixedly secured to the flat plate at a portion of the tube, and means for adjusting the length of the tube by stretching that tube portion.
 4. An apparatus as in claim 2 wherein the plurality of containers into which the liquid is to be distributed are arranged annularly along the circumference of a turntable so as to be disposed immediately below the pipette one after another, and support means for the container disposed immediately below said pipette for elevating the container at that location. 